In a lead-acid battery or cell comprising a carbon fibre electrode or electrodes, a very low electrical resistance and mechanically durable connection is required between the carbon fibre electrode material and a connector or lug (herein generally referred to as lug) to the external circuit. This can be difficult to achieve particularly when the carbon fibre electrode material has an interfibre spacing of less than 100 microns, for reasons that include that carbon strongly repels metal from its surface and/or the need to overcome surface tension to enable lug metal to penetrate between the carbon fibres (whether interfibre or intrafibre i.e. the latter referring to between filaments of individual fibres if the carbon fibres are multifilamentary).
Achieving high penetration between fibres to minimise remaining voidage between the lug material and the fibres of the lug connection is also important as one way of preventing battery electrolyte from subsequently entering the lug to fibre connection and deteriorating the connection.
U.S. Pat. No. 3,926,674 discloses a method for manufacturing electrical connection elements on battery electrodes of glass fibre by molten lead injection.